This is really lovely the unicorn is one of my favourite mythical creatures! I love how the rainbow extends over one shoulder across the back of the t-shirt Check out my entry: [link]I would've loved to have done a unicorn too, but opted for something a little different.....

I think this version fits better than the feather one With feathers it looks like you have given an area of the drawing too much detail comparing with the rest of the image. Keep it simple and good luck with the shirt Please check out my rainbow pegasus shirt: [link]